Method for representing moving objects in bitmap format on a matrixed display device

ABSTRACT

The invention creates a method for representing moving objects in bit-mapped format on a matrixlike display device, having the following steps: calculation of a plurality of bit maps for a certain number of a various object representations along a predetermined path curve in advance; storage of the plurality of bit maps in memory in advance; and execution of a representation processing with a display sequence of object representations along the path curve by reading and displaying correspondingly memorized bit maps.

PRIOR ART

The present invention relates to a method for representing movingobjects in bit-mapped format on a matrix-like display device.

Although it can be employed on arbitrary objects in bit-mapped formatand arbitrary matrixlike display devices, the present invention and theproblems fundamental to it will be explained below with regard to adashboard display device, or monitor, located on board a motor vehicle,for representing a pointer.

For a fluid or sliding representation, that is, a representation ofpointer animation without perceptible skipping on a dashboard monitor onboard a motor vehicle, it is generally necessary to go to considerablecomputation effort, which requires the use of dedicated graphicshardware and software.

The following operations must typically be performed.

The pointer, for instance the speedometer pointer, which is present inthe form of a bit map, must be rotated by computation into angularpositions corresponding to various speeds.

In this bit map, the pointer has much higher resolution (supersampling)than in the case of the actual representation on the display device, sothat then, in other words after the computational rotation, a filtrationin the local region for the sake of edge smoothing (anti-aliasing) canbe appropriately performed. Typically, one ray of 3×3=9 pixels in thebit map corresponds to a single pixel of the display device. Each pixelcan assume 256 bit values for each individual one of the threefundamental colors, red, green and blue.

Furthermore, a computational superposition of the pointer, in each ofits angular positions, with a suitable background image such as a scaleis necessary.

The problems fundamental to the present invention are in general thatthis computation effort in representing objects in bit-mapped format ona matrixlike display device using conventional hardware with a structuresimilar to a personal computer, cannot be accomplished fast enough. As aresult, the object to be represented moves along the predetermined pathcurve slowly and in visible stages, which makes the observer uneasy.

In the prior art, anti-aliasing processing with hardware or software canbe executed sufficiently fast only in the case of edge smoothing ofobjects present in vector data form, such as a line or a circle, or inthe representation of filler patterns, which represent the repetition ofa relatively small-area basic pattern.

However, the only sensible way to represent pointers, including theirhubs, with arbitrary color patterns and shapes, as is desired bycustomers and designers, is in the form of a bit map.

ADVANTAGES OF THE INVENTION

The method according to the invention for representing objects inbit-mapped format on a matrixlike display device in accordance withclaim 1 has the advantage that it reduces the online computation effortfor representing objects in bit-mapped format on a matrixlike displaydevice considerably and thus makes a flowing representation withoutskipping possible on conventional hardware. Arbitrary graphical objectsof high quality can be utilized for animation purposes. All of theseobjects can be stored in the general form of a bit map and need not bedescribed inconveniently in vector form.

The concept on which the present invention is based is that thetime-consuming calculations can be performed in advance offline for acertain number of different object representations along a correspondingpath curve. The object representations, which are thus present inpreprocessed positions at discrete locations, are each stored as arespective bit map. During the running time of the representationprogram, only the bit map that is to be displayed for situationalreasons is read out of the memory and displayed. Expediently, this bitmap is superimposed on the also preprocessed and stored backgroundimage.

Advantageous refinements and improvements to the method defined by claim1 are found in the dependent claims.

In accordance with a preferred refinement, in the calculation of theplurality of bit maps in advance, a filtration is performed for the sakeof edge smoothing in the local region. This has the advantage that eventhis time-consuming calculation operation can be performed offline.

In a further preferred refinement, an associated precalculated andpre-stored background image is superimposed on the various objectrepresentations. This is expedient, since the background image changessubstantially more seldom than the foreground image that includes theobject moving along the path curve.

In a further preferred refinement, the spatial difference betweenadjacent object representations along the path curve, which areprecalculated and pre-stored as a respective bit map, is substantiallysmaller than the applicable object representations. In other words, anappropriate correlation between two adjacent object representationsalong the path curve must prevail, if appropriate results are to beattained. A contrary example would be two pointer positions, oneindicating “12 o'clock” and the other “3 o'clock”.

In another preferred refinement, for displaying object representationswhich are located between two object representations having a respectivepre-calculated and pre-stored bit map, a paired interpolation betweenthe corresponding pixel values (picture elements) is performed. By meansof this kind of interpolation process, the object path resolution can bemade arbitrarily fine. Furthermore, this saves space in memory, which isneeded for the precalculated bit maps.

In a further preferred refinement, the pixel values are presentseparately in accordance with certain colors, preferably the threefundamental colors of red, green and blue, and the interpolation isperformed separately for each color.

In a further preferred refinement, for the interpolation, the mean valuefor each pixel, weighted in accordance with the intermediate position,is calculated. This corresponds to a simple linear interpolation as afunction of the position of the intermediate position.

In a further preferred refinement, a compression of the pre-stored bitmap data is performed. This then leads to good results especially iflarge image areas with a single-color background are available.

DRAWINGS

Exemplary embodiments of the invention are shown in the drawings anddescribed in further detail below.

Shown are:

FIG. 1 a, a bit map B(i) for representing a pointer in bit-mapped formaton a matrixlike display device of a dashboard instrument on an i^(th)point of a path curve;

FIG. 1 b, an intermediate bit map Z(i, a), interpolated linearly inonline operation, for representing a pointer in bit-mapped format on amatrixlike display device of a dashboard instrument at an (i+a)^(th)point of the path curve, where a=0.5; and

FIG. 1 c, a bit map B(i+1) for representing a pointer in bit-mappedformat on a matrixlike display device of a dashboard instrument at anadjacent (i+1)^(th) point of the path curve.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

One embodiment of the method according to the invention for representingobjects in bit-mapped format on a matrix-like display device will bedescribed below with reference to FIGS. 1 a-1 c, in terms of its use forrepresenting a pointer on a dashboard display device, or dashboardmonitor, on board a motor vehicle.

First, a calculation of a plurality of bit maps for a certain number ofdifferent pointer representations along a predetermined path curve,namely along a circular scale, for instance, as a background is doneoffline. Already in these advance calculations of the plurality of bitmaps, a filtration is performed for the sake of edge smoothing in thelocal region, so as to make the later online calculations as slight aspossible and thus make the display speed as fast as possible.

The spatial difference between adjacent pointer representations alongthe path curve, which are precalculated and pre-stored as a respectivebit map, is substantially smaller than the applicable pointerrepresentations. The precise difference must be optimized from one caseto another to suit the various pointer representations.

The calculated plurality of bit maps is stored in memory in advance in amemory device that is part of the dashboard monitor. In general, acompromise must be made between the available memory space and thedesired fine resolution.

In online operation, during motor vehicle travel, the execution of arepresentation processing is then done, with a display sequence ofpointer representations along the path curve, by reading and displayingsuitably stored bit maps. If the pointer is the speedometer pointer, itis accordingly the pointer bit map corresponding to the instantaneousspeed that is read and displayed at a given time.

The corresponding scale, which is an associated precalculated andpre-stored background image, has the pointer representation superimposedon it.

Let it be assumed as an example that in FIG. 1 a a bit map B(i) forrepresenting the pointer in bit-mapped format on the matrixlike displaydevice of the dashboard instrument is shown at an i^(th) point of thepath curve, specifically to indicate 120 km/h.

Let it also be assumed that in FIG. 1 b, a bit map B(i+1) forrepresenting the pointer in bit-mapped format on the matrixlike displaydevice of the dashboard instrument is shown at an adjacent (i+1)^(th)point of the path curve, specifically to indicate 125 km/h.

A bit map for representing a pointer in bit-mapped format on thematrixlike display device of the dashboard instrument at an interveningpoint of the path curve, specifically to indicate 122.5 km/h, is notstored in memory.

In this embodiment of the invention, a display of such a pointerrepresentation located between two pointer representations each with aprecalculated and pre-stored bit map, is done by means of a pairedinterpolation between the corresponding pixel values. The pixel valuesare present separately in accordance with certain colors, preferably thethree fundamental colors of red, green and blue, and preferably theinterpolation is performed separately for each color.

In this example, however, for the sake of simplicity let it be assumedthat the pointer representation is done in only one fundamental coloreach, or that the values for all three fundamental colors are the same.The resultant 256 values are located between 0 and 255. 0 designates thedarkest value and 255 the brightest value. It should also be noted thatfor the sake of simplicity, not all the pixel values are shown in thebit maps of FIGS. 1 a-1 c.

FIG. 1 b is an intermediate bit map Z(i, a) interpolated linearly inonline operation, for representing the pointer in bit-mapped format onthe matrixlike display device of the dashboard instrument at an(i+a)^(th) point of the path curve; in this case, a=0.5, because 122.5km/h is located precisely in the middle between 120 km/h and 125 km/h.

The pixel values Z_(mn)(i, a) of the intermediate bit map Z(i, a) canaccordingly be calculated as followed:Z _(mn)(i,a)=(1−a)*B _(mn)(i)+a*B _(mn)(i+1)  (1)where m is the line indicator and n is the column indicator. In otherwords, the pixel values Z_(mn)(i, a) are precisely the mean values ofthe pixel values B_(mn)(i) and B_(mn)(i+1).

Although the present invention has been described above in terms of apreferred exemplary embodiment, it is not limited to that but insteadcan be modified in manifold ways.

In particular, it is understood that instead of the above linearinterpolation, any other interpolation is possible.

Nor is the interpolation absolutely necessary; it depends on the memorycapacity and on the desired fine resolution. For example, it is notnecessary to perform an interpolation below a certain thresholddifference, which in the above example can be 1 km/h.

To save storage space, a compression/decompression of the pre-stored bitmap data, that is, pointer data and/or background data, can be employed.

1. A method for representing an object in bit-mapped format on a matrixlike display device, having the following steps: calculating a pluralityof bit maps for a certain number of various object representations alonga predetermined path curve in advance; storing the plurality of bit mapsin memory in advance; and executing a representation processing with adisplay sequence of object representations along the path curve byreading and displaying correspondingly memorized bit maps, wherein theobject moves along the path curve during the representation processingand displaying of the correspondingly memorized bit maps.
 2. The methodof claim 1, characterized in that the calculating of the plurality ofbit maps in advance, a filtration is performed for the sake of edgesmoothing in the local region.
 3. The method of claim 1, characterizedin that an associated precalculated and pre-stored background image hasthe various object representations superimposed on it.
 4. The method ofclaim 1, characterized in that the spatial difference between adjacentobject representations along the path curve, which are precalculated andpre-stored as a respective bit map, is substantially smaller than theapplicable object representations.
 5. The method of claim 1,characterized in that for displaying object representations, which arelocated between two object representations having a respectiveprecalculated and pre-stored bit map, a paired interpolation between thecorresponding pixel values is performed.
 6. The method of claim 5,characterized in that the pixel values are present separately inaccordance with certain colors, preferably the three fundamental colorsof red, green, blue, and the interpolation is performed separately foreach color.
 7. The method of claim 6, characterized in that for theinterpolation, the mean value for each pixel, weighted in accordancewith the intermediate position, is calculated.
 8. The method of claim 1,characterized in that a compression of the pre-stored bit map data isperformed.
 9. The method of claim 1, characterized in that the method isemployed on a dashboard display device, located on board a motorvehicle, for representing a pointer.
 10. The method of claim 9, whereinthe pointer is a speedometer pointer, and wherein a pointer bitmapcorresponding to a speed is read and displayed at a given time.
 11. Themethod of claim 9, wherein an associated pre-calculated and pre-storedbackground image is a corresponding speed scale.
 12. The method of claim1, wherein the various object representations are object representationsof the same object.
 13. The method of claim 1, wherein the object is apointer and wherein the pointer moves along a scale, wherein indifferent position of the pointer, graphical representations arecalculated and stored in advance.